Jarred Blancard (young Henry Bowers) hated having to call Marlon Taylor (young Mike Hanlon) a "nigger", and would often apologize to him before and after filming for his character's excessive use of the slur.

When Beverly is listening to the voices in the drain, one boy identifies himself as Matthew O'Connor. Matthew O'Connor is also the name of the Supervising Producer of the film. A girl in the drain identifies herself as Vicky Burrows. Victoria Burrows did casting for the movie.

Tim Curry was reluctant to take the role of Pennywise initially because he didn't relish the thought of being buried under so much makeup. When he played Darkness in Legend (1985), it was a difficult and demanding role, and the hours in makeup was still fresh in his mind. To compromise, Tommy Lee Wallace minimized the amount of makeup on Curry, and a lot wasn't necessary anyway because Curry's performance was so strong.

To get the effect of "It" moving through the pipework, a dolly crane was built and pushed through the piping. It was a difficult shot to get right because it was so cramped. It was also done from "It's" point-of-view because Tommy Lee Wallace believed that what we imagine is often scarier than what we see, a trick he learned from his old mentor, John Carpenter.

In the scene with Pennywise (Tim Curry) and Georgie (Tony Dakota), Curry was so in character that Dakota remarked "Tim, you're scaring me". Curry responded with "Gee I'm so sorry, but that's what I'm supposed to be doing. And you're supposed to be scared".

When Beverly goes back to the house she grew up in, Tommy Lee Wallace wanted Annette O'Toole alone on the street, without any other actors or extras around to make it creepier. Also, when she meets Mrs Kersh, he filled the scene with incidental details to illustrate to the audience that there's something wrong in this house, e.g. her teeth are all rotten, just like Pennywise's.

The blood oozing over Georgie's photo was quite unusual to see in a TV movie in 1990. It (1990) paved the way for TV movies and mini-series in the future to push the envelope far more than ever before.

Since It first aired, there has been much speculation as to the sewer building pump house. Fans wanted to know the location of the real building and rumor was that it was a built set that had been immediately torn down after filming. The real building is actually the old Buntzen Lake Hydro Plant in Canada, which looked vaguely different in 1990 but after it shut down in the early 2000's now retains a more faded look. People can go up to it, but are prohibited from going inside without authorization.

Pt 1 was the fifth highest rated program on Sunday, November 18th, with an 18.5 rating and watched in 17.5 million households. Pt 2 was the second highest rated program on Tuesday, November 20th, with a 20.6 rating and watched in 19.2 million households.

All of the cast have fond memories of working on It (1990), saying it was one of the best experiences of their lives on the DVD commentary. This was mirrored almost 30 years later, when all the kids who worked on It (2017) called the three-month shoot the best summer of their lives, and claimed that they were all best friends onscreen and in real life.

When Pennywise appears as a ghostly image in the sewers, Tommy Lee Wallace originally wanted the roots growing down to begin writhing around him, something Eddie hopes they wouldn't start doing. The budget didn't allow it, however, and Wallace thought the effect they had to use instead was rather cheesy to look at.

The adult actors had to be careful what they touched during the sewer scenes because the place was so rusty, there was a very real danger of tetanus infection. Because of that, it was not a fun scene to film.

The Chinese restaurant scene was Richard Thomas' favourite scene in the movie. It was filmed in three days. There were puppeteers under the table working Pennywise's fortune cookies. The scene was shot on a handheld camera to make it scarier.

The asylum orderly, Koontz, drops a roll of coins when he sees Pennywise. Though not covered in the movie, the book explains that Koontz uses quarter rolls to beat the patients as it is as effective as a baton and more compact.

Stephen King's novel IT is connected to his Dark Tower universe. The novel has an image of a turtle supporting the earth. A poem explaining this, "See the Turtle of enormous girth/ Upon his back he holds the Earth," appears in both IT and the third Dark Tower novel, The Waste Lands. That book also expands on the idea of multiple dimensions, each guarded by an animal avatar, held together by the Dark Tower in the center, rather like the spokes of a wheel. The final Dark Tower novel, The Dark Tower, features a character named Mordred who, like Pennywise, shifts from human to spider form, and another character, Dandelo, who, like Pennywise, has "deadlights" behind his eyes that will drive a mortal to madness. Stephen King has stated that Mordred is not Pennywise, but that the two may be the same species (in the novel, Pennywise is revealed to be a pregnant female, therefore opening up the possibility for multiple Its) The character Mike Hanlon appears in both IT and Insomnia, which introduces Dark Tower character Patrick Danville.

Tommy Lee Wallace admitted he had never read the novel before making the film. He preferred to let the script speak for itself. In the DVD Commentary, Wallace revealed that he did read the novel later on and admitted that he believes the miniseries fell short of the source material.

If you notice some scenes (like the final battle), you'll find the use of the green color very easily. Stephen King has said that green is a color that, for him, represents death, unease, or the supernatural. It's also been used by the author in other books, and by directors in movies based on his books. This is generally thought of as an influence from H.P. Lovecraft.

Tommy Lee Wallace's first TV movie. Because it was his first, he tried to get It (1990) as close to perfect as possible. However, he later said he believed they fell short in comparison to King's original novel.

When ABC and Lorimar first announced the film, it was to be a 10 hour miniseries directed by George A. Romero. Romero did extensive pre-production work and closely collaborated with Lawrence D. Cohen to develop the script, but he had to bow out due to a scheduling conflict with the remake of Night of the Living Dead (1990). This mirrored Romero's experience on another Stephen King property, the previous year's Pet Sematary (1989), which he was also slated to direct.

Tommy Lee Wallace wasn't sure about turning Audra from a heroine coming to rescue Bill into a victim who needs to be rescued by Bill. He didn't think it worked dramatically in the movie, or the novel for that matter.

Ironically, Tim Curry suffered from a debilitating case of coulrophobia (a fear of clowns) most of his life, and his contract forbade mirrors or other reflective surfaces anywhere near him during filming, lest he catch a glimpse of himself in makeup. In fact, a makeup tech was very nearly fired for having a makeup mirror in hand while applying Curry's makeup one day.

In the scene at the Chinese restaurant when everyone's fortune cookie is showing them something, Mike's exposes the fetus of an unhatched bird. This could refer to the scene in the novel when It attacks young Mike in the shape of a giant bird.

At one point, while running from Henry Bowers and his gang, Richie Tozier (played by Seth Green) accidentally bumps into the school's principal (played by William B. Davis). A few years later, Green portrayed a secondary character in Episode 1x01 of The X-Files (1993), while Davis played the recurring role of 'The Cigarette Smoking Man', the show's main villain.

The theater scenes racked up many dull hours of waiting and retakes for the child extras. Tim Curry often came onto the stage in full costume and conducted singalongs with the extras, most of whom didn't know who he was. They thought he was actually a clown hired to entertain them.

In the novel, two of the children have connections to other Stephen King characters. Mike Hanlon's father served in the Army with Dick Halloran, the cook from The Shining. Eddie Kasprack was also friends with young Paul Sheldon, who as an adult was the protagonist in Misery.

When Harry Anderson (as adult Richie Tozier) is talking with his manager in L.A. about going back to Derry his manager asks Richie who'll host the tonight show. Remember this was filmed in or around 1990. Richie says "Let Jay Leno". Jay Leno took over the Tonight show in 1992.

It was originally proposed that Tim Curry plays all the forms It shape shifts into except the giant spider, but they decided it'd be quicker to have different actors playing those forms than to wait for Curry to have the make-up applied on him.

Before the adult character Ben Hanscom is introduced, there's a shot of New York City's Twin Towers of the World Trade Center. It is one of at least three adaptation films of Stephen King's books to include shots of the World Trade Center, the other two being Dolores Claiborne and Cat's Eye, among others. Unfortunately, 11 years after It was released, the Twin Towers were hit by planes and destroyed on September the 11th, 2001.

Various scenes of It feature the use of claymation, including the scene where Eddie is taking a shower and the clown pulls the drain open to fit his head through, the scene where the clown does a mid-air somersault down a drainpipe in the sewer building, and the scene where Belch is folded completely in-half and killed by the clown. Claymation was chosen because it was cheaper than CGI and because certain scenes in the film such as these would be too difficult and expensive to create otherwise.

Spoilers

The trivia items below may give away important plot points.

The spider at the climax was a fully operable puppet. It was the last scene to be filmed. John Ritter was disappointed that the final battle had to be fought with a puppet and not Tim Curry, because he felt Pennywise was the real villain of the show, and not some fake spider. The novel's ending was also much too cerebral to tackle on a television budget. Tommy Lee Wallace also felt disappointment with the movie's ending. The way he imagined it was different to the way it turned out, because they didn't have the money to do it as it was storyboarded.

The ending of the novel included the appearance of the Turtle, which was It's natural enemy and created the universe. When John Ritter asked about the Turtle's appearance in the film, the studio asked if he was crazy.

When Beverly, Ben and Eddie hug Bill outside the hotel, it was Harry Anderson's idea that Richie doesn't hug him. Tommy Lee Wallace wasn't sure about that idea at first but later came to agree with it because Richie had become the cynic of the group now that Stan was dead.

When Beverly realizes her father is unable to see the blood in the bathroom, she claims a large spider came up from the drain. This turns out to not be completely false, as It is revealed to be a giant spider at the end of the movie.